The maximum value storage sensor are disclosed in Laid-open Japanese Patent Application under publication Nos. Hei 6-331581 and Hei 7-128156. The sensors have a structure formed by connecting a plurality of conductive elements such as carbon filaments having an appropriate resistance are connected in parallel to a pair of terminals at slightly different degree of slackness, and also attached to the object component member to be detected of a structure so that a stress is induced to each of the conductive elements by a strain or displacement of the object component member. When a stress is induced, corresponding to the degree, the conductive elements, each having a different degree of slackness, break sequentially in increasing order of degree of slackness, and a resultant change in the electrical resistance is detected as the electrical resistance changes across the terminals, or as the voltage change depending on the resistance changes. The resistance across the terminals indicates that the broken conductive elements can be determined from the resistance, which gives the maximum value of strain or displacement of the component member.
These maximum value storage sensors can be universally used with various types of structures and have many advantages including a considerably high detection accuracy and a simple construction. However, since these sensors use the basic principle that the maximum strain will be detected through the sequential self-breakage of conductive elements, each which has a slightly different degree of slackness caused by the strain of the object component member, the sensors have a disadvantage in that a stable detection accuracy can not necessarily be satisfactorily maintained. In other words, the key factor of a stable detection accuracy in these maximum value storage sensors is setting the desired degrees of slackness for each of the conductive elements; furthermore, the detection accuracy is also subject to the difference of tensile strength of the conductive elements. Setting the conductive elements to a minutely different degrees of slackness for each conductive element is very difficult, and if a sequential breakage of the conductive elements does not occur as expected, there is a possibility that conductive elements will not necessarily break in the sequentially predetermined order; and keeping a uniform tensile strength of the conductive elements is also rather difficult which leads to an inability of sufficiently securing a stable detection accuracy.
The present invention has been made in consideration of these circumstances and one of its objects is to provide a more stable and higher detection accuracy to the maximum value storage sensor when detecting the maximum strain by generating an invariable electrical resistance change correlative to the strain of the detection object in a conductive body having a plurality of conductive elements as mentioned above.
Another object of the present invention is to provide structures for enhancing the serviceability relative to the above-mentioned maximum value storage sensor.
A further object of the present Invention is to provide an output circuit for processing sensor information from the above-mentioned maximum value storage sensor into information which can be processed by an electronic circuit.